Flying frog

Flying frog

It is said that the high magnetic field (and gradient) can make a frog fly. Let's see the possibility:

What exist most in biological tissue is water (human: 78% newborn, 65% one year old, 60% adult).

Here we simplify the problem by assuming we want to float water instead.

To make a drop of water fly, one has to counteract the gravity on the water, using, in this case, magnetic force. Therefore:

F_G=F_M, where

and

Hence,

Note that it has nothing to do with volume of the biological tissue.

Using the density of water g= 1.0x10³ kg/m³ and the susceptibility χ=−9.035×10⁻⁶, one finds

BdB/dz = 1.4x10³ T²/m.

Here is an list of the parameters of the magnets that I have worked with.

	Stern-Gerlach I	Stern-Gerlach II	DC magnet
B (T)	1	2	33
dB/dz (T/m)	345	50	300
BdB/dz (T2/m)	345	100	9900

We can see that the DC magnet is able to do this in the center of the magnet. For this magnet, the threshold is about 13 T.